1. Field of the Invention
The present invention relates to a flexure blank for constructing a suspension for a circuit wire integrated type magnetic and a method of manufacturing the same and particularly to a flexure blank structured such as to be electrically connected with a relay flexible circuit board for connecting to an external circuit in a reliable manner, and a method of manufacturing the same.
2. Description of the Related Art
This kind of suspension for the circuit wire integral type magnetic head is constituted by a load beam and a flexure blank, and the flexure blank is connected to an external circuit via the relay flexible circuit board.
FIG. 2 is a cross sectional view which shows a schematic arrangement of the connecting portion of the flexure blank mentioned above and the relay flexible circuit board. A terminal portion or the connecting portion of the conventional flexure blank is structured such that an opening portion 22 for connection is provided at a predetermined position of an insulating base layer 20 made of a polyimide resin or the like, a conductive layer 23 made of a copper or the like and including a predetermined circuit wire pattern is formed on an upper surface of the insulating base layer 20 in such a manner as to surround the opening portion 22, and as shown in FIG. 2, an anticorrosive conductive layer 25 made of a gold or the like is formed on an upper surface of the conductive layer 23 in this connecting portion via a barrier conductive layer 24 made of a nickel or the like.
The conductive layer 23, the barrier conductive layer 24 and the anticorrosive conductive layer 25 mentioned above can be formed in accordance with an additive method such as an electrolytic plating or the like, and this kind of flexure blank is coated with a surface protecting layer 26 made of a polyimide resin or the like including the circuit wire pattern in such a manner as to properly expose the connecting portion mentioned above.
However, in accordance with the structure of the connecting portion of the flexure bland mentioned above, there is a case that an end portion 21 of the insulating base layer 20 positioned at the opening portion 22 for connection protrudes and is formed so as to fringe the conductive layer 23, the barrier conductive layer 24 and the anticorrosive conductive layer 25 in the opening portion 22.
As mentioned above, when the end portion 21 of the insulating base layer 20 protrudes to the opening portion 22 for connection, there is generated a case that a solder is neither sufficiently applied nor expended to a whole of the connecting portion constituted by the conductive layer 23, the barrier conductive layer 24 and the anticorrosive conductive layer 25 and an electric connection can not reliably performed since a wetting property of a solder 29 is bad in the protruding end portion 21 of the insulating base layer 20 in the case of bringing the relay flexible circuit board for connecting to the external circuit in which a predetermined circuit wire pattern 28 is formed on an upper surface of the insulating base member 27 into contact with the opening portion 22 in the connecting portion of the flexure blank mentioned above by using the solder 29 in the manner shown by an arrow.